Battery capacity tester with data logging
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RCinFLA
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The DL24P is pretty good. The PC app is pretty poor. There are several third party PC programs that are better. When testing and data logging you want data file to have three decimal places on cell voltage and several of the PC apps only show two decimal places in dump file. The unit's ADC is 24bit sigma delta converter so it is pretty accurate.
I suggest soldering a 20-30 amp auto fuse across the STPS41H100CG dual diode on center left side of PCB topside. The diode gets very hot at high current and does not have much heat sinking. The diode is only for reverse polarity protection and with the auto fuse the load MOSFET body diode will conduct for an accidental reverse battery hookup so fuse blows.
Also make sure you use the four wire remote cell voltage sensing to eliminate effects of voltage drop on high load current cables to battery.
One thing that is very important. You must connect 12v power supply BEFORE plugging in USB cord to computer. If you plug in computer USB before connecting the tester's 12vdc power supply it usually blows out the serial to USB converter chip CH340G and you will no longer have USB communications. I have had to replace a couple of these CH340G SOIC's on the board because of this issue.
I suggest soldering a 20-30 amp auto fuse across the STPS41H100CG dual diode on center left side of PCB topside. The diode gets very hot at high current and does not have much heat sinking. The diode is only for reverse polarity protection and with the auto fuse the load MOSFET body diode will conduct for an accidental reverse battery hookup so fuse blows.
Also make sure you use the four wire remote cell voltage sensing to eliminate effects of voltage drop on high load current cables to battery.
One thing that is very important. You must connect 12v power supply BEFORE plugging in USB cord to computer. If you plug in computer USB before connecting the tester's 12vdc power supply it usually blows out the serial to USB converter chip CH340G and you will no longer have USB communications. I have had to replace a couple of these CH340G SOIC's on the board because of this issue.
Hi' everybody,
Atorch make several different variants of testers. The DL-24P is a good tester, but only suitable really for cell capacities below 80Ah, because it isn't able to sustain a discharge current above 16Amp (=0.2C) which is the standardized test discharge current.
You can still use it of course, but your resulting capacity will then show a higher Ah capacity, than what the cell would be able to provide at the proper test current.
I also tried their tester with multiple MOSFETs to obtain higher discharge current, but I had to completely give up on that path, the MOSFETs start producing some very noisy quiescent currents, and I never managed to run them stable with currents above 25Amp, and they end up self-destructive instead. I tried to get proper support from Atorch, but although they did try to help, it was fruitless, and just a complete waiste of time and money.
I now use and have several quite professional testers capable of up to 50Amp both charging and discharging, they work really smooth and have plentifully settings for good analysis of your battery, and they weren't even overly expensive.
If you are using cells up to 230Ah I would highly recommend such tester, and even cells of 280 and 320 you could test, but then with slightly insufficient discharge current (64Amp CC on 320Ah).
I also use it to analyse selfdischarge on a cell. Bad cells can easily draw over 1 amp continuously to maintain 3.65V, whereas good cells drop below 100mA without difficulty after a completed full charge.
The discharge curve itself also reveals such problem, as the voltage on the cell shows a constantly dropping voltage, where good cells does not drop much in voltage untill the very end of the discharge cycle.
The discharge curves shown here are both for 161Ah cells fully charged, rested and recharged before starting the discharge test, and you can clearly see the difference.
It also turned out that seller had scratched out the QR codes on the two worst performing cells, as if that would make any sense ?.
Hope you can use this information in your quest to stop fraudulent or aged cell offerings presented as grad-A and brand new.
Wath-Out.
Atorch make several different variants of testers. The DL-24P is a good tester, but only suitable really for cell capacities below 80Ah, because it isn't able to sustain a discharge current above 16Amp (=0.2C) which is the standardized test discharge current.
You can still use it of course, but your resulting capacity will then show a higher Ah capacity, than what the cell would be able to provide at the proper test current.
I also tried their tester with multiple MOSFETs to obtain higher discharge current, but I had to completely give up on that path, the MOSFETs start producing some very noisy quiescent currents, and I never managed to run them stable with currents above 25Amp, and they end up self-destructive instead. I tried to get proper support from Atorch, but although they did try to help, it was fruitless, and just a complete waiste of time and money.
I now use and have several quite professional testers capable of up to 50Amp both charging and discharging, they work really smooth and have plentifully settings for good analysis of your battery, and they weren't even overly expensive.
If you are using cells up to 230Ah I would highly recommend such tester, and even cells of 280 and 320 you could test, but then with slightly insufficient discharge current (64Amp CC on 320Ah).
I also use it to analyse selfdischarge on a cell. Bad cells can easily draw over 1 amp continuously to maintain 3.65V, whereas good cells drop below 100mA without difficulty after a completed full charge.
The discharge curve itself also reveals such problem, as the voltage on the cell shows a constantly dropping voltage, where good cells does not drop much in voltage untill the very end of the discharge cycle.
The discharge curves shown here are both for 161Ah cells fully charged, rested and recharged before starting the discharge test, and you can clearly see the difference.
It also turned out that seller had scratched out the QR codes on the two worst performing cells, as if that would make any sense ?.
Hope you can use this information in your quest to stop fraudulent or aged cell offerings presented as grad-A and brand new.
Wath-Out.
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Very accurate description.
Good suggestion. For anyone interested I did some measurements of the diode temperature (measured through the PCB).
Battery cell capacity testing.
I have started trying out a new tester, the ET5410 (about $185 including air freight). At 35 amps it takes about 8 hours to test a cell, but I'm going to test lower amps due to my fuse holder heating up. It's much better than the $30 tester from ATorch. This $30 tester has a tendency to burn out...
diysolarforum.com
That is the primary advantage of this tester, the sense leads certainly help with accuracy. Still cheap enough and accurate enough.
This I didn't know, sounds logical though. Thanks for the tip.
matt2006
DIY Solar since 2016
I use icharger 4010Duo
To test hundreds of 12v and 24v lifepo4 recycled batteries and the discharge is regenerative back to my 24V battery as the source power.
This is for my business in reselling pre owned lithium batteries.
They have an SD card slot for data logging.
To test hundreds of 12v and 24v lifepo4 recycled batteries and the discharge is regenerative back to my 24V battery as the source power.
This is for my business in reselling pre owned lithium batteries.
They have an SD card slot for data logging.
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